<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir="ltr" data-setdir="false">Dear all,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">This is my first question in this mailing list. </div><div dir="ltr" data-setdir="false"><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;">I am using QE 6.3 now, although I would like to upgrade to the latest versions soon.</span></span><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I would like to clarify about matdyn.x and lambda.x results. </div><div dir="ltr" data-setdir="false">For example, I am trying to compute H3S hydride superconductor (Tc ~200K at 200GPa).</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">(This is a preliminary attempt to get used to the calculations, convergence is not achieved yet in the below results but it is not the core of this question) </div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">My question concerns the output of the "<b>lambda</b>" file from <b>matdyn.x</b> calculation, as shown below.</div><div dir="ltr" data-setdir="false">------------------------------------------------------------------------------------------------------------</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><div><div> <b> Electron-phonon coupling constant, lambda</b></div><div><br></div><div> Broadening 0.0050 lambda 2.9575 dos(Ef) 3.7441 omega_ln [K] 1181.8314</div><div> Broadening 0.0100 lambda 2.0277 dos(Ef) 3.1220 omega_ln [K] 1211.1636</div><div> Broadening 0.0150 lambda 1.8563 dos(Ef) 3.1665 omega_ln [K] 1264.6372</div><div> Broadening 0.0200 lambda 1.7776 dos(Ef) 3.2436 omega_ln [K] 1299.6930</div><div> Broadening 0.0250 lambda 1.7561 dos(Ef) 3.2997 omega_ln [K] 1319.3964</div><div> Broadening 0.0300 lambda 1.7416 dos(Ef) 3.3125 omega_ln [K] 1329.9055</div><div> Broadening 0.0350 lambda 1.7180 dos(Ef) 3.2854 omega_ln [K] 1335.8834</div><div> Broadening 0.0400 lambda 1.6872 dos(Ef) 3.2343 omega_ln [K] 1339.8464</div><div> Broadening 0.0450 lambda 1.6540 dos(Ef) 3.1731 omega_ln [K] 1342.8883</div><div> Broadening 0.0500 lambda 1.6216 dos(Ef) 3.1109 omega_ln [K] 1345.4217</div></div><br></div><div dir="ltr" data-setdir="false">------------------------------------------------------------------------------------------------------------</div><div dir="ltr" data-setdir="false">If my understanding is correct, the lambda and omega_ln values here are already the ingredients needed to be plugged into the McMillan formula. Once the convergence is satisfied, their values shouldn't change much even with different broadening values. <br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">From the examples of Tc calculation with QE, there is another calculation step using <b>lambda.x</b> after this <b>matdyn.x</b> step that yields Tc value.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">For example, exercise 1 page 6 of <a href="https://indico.ictp.it/event/8301/session/96/contribution/534/material/0/0.pdf" rel="nofollow" target="_blank">https://indico.ictp.it/event/8301/session/96/contribution/534/material/0/0.pdf</a> in 2018, or </div><div dir="ltr" data-setdir="false">example 3 step 7 for Aluminum in PHonon (<a href="https://gitlab.com/QEF/q-e/-/tree/develop/PHonon/examples/example03" rel="nofollow" target="_blank" class="">https://gitlab.com/QEF/q-e/-/tree/develop/PHonon/examples/example03</a>)</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">However, after reading the past messages in this mailing list, while there were multiple reports of errors encountered when using <b>lambda.x</b></div><div dir="ltr" data-setdir="false">I also read the message from Prof. Eyvaz Isaev that as of QE v4.2 (2010), the function of lambda.x was already incorporated in <b>matdyn.x</b></div><div dir="ltr" data-setdir="false"><a href="https://www.mail-archive.com/users@lists.quantum-espresso.org/msg06376.html" rel="nofollow" target="_blank">https://www.mail-archive.com/users@lists.quantum-espresso.org/msg06376.html</a><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><i>If that is still true, is it then no longer necessary to perform <b>lambda.x</b> run provided that convergence is achieved in the "<b>lambda</b>" file from <b>matdyn.x</b> output? </i></div><div dir="ltr" data-setdir="false"><i><br></i></div><div dir="ltr" data-setdir="false"><i>Wouldn't it suffice to directly substitute the converged lambda and omega_ln values to the McMillan formula after matdyn.x calculation?</i></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Thank you for your guidance,</div><div dir="ltr" data-setdir="false">Best regards,</div><div dir="ltr" data-setdir="false">Alpin N. Tatan</div><div dir="ltr" data-setdir="false">University of Tokyo.</div></div></body></html>